Earth-boring rotary tools having fixed blades and rolling cutter legs, and methods of forming same

Abstract

An earth-boring rotary tool includes a tool body, at least one fixed blade associated with the tool body and configured to carry a fixed cutting element, and at least one leg configured to carry a rolling cutter. The tool body has a slot extending longitudinally generally parallel to a longitudinal axis defining an axial center of the tool body. The slot is at least partially defined by a first sidewall, a second sidewall opposing the first sidewall, a third sidewall extending between the first sidewall and the second sidewall, and an axial end wall of the tool body. A portion of the leg is disposed within the slot of the tool body and abuts the first sidewall of the tool body. A wedge is disposed within the slot and pins the leg to the tool body within the slot.

What is claimed is: 
     
       1. An earth-boring rotary tool, comprising:
 a tool body having a slot at least partially defined by a first sidewall, a second sidewall opposing the first sidewall, a third sidewall extending between the first sidewall and the second sidewall, and an axial end wall of the tool body, the slot extending longitudinally parallel to a longitudinal axis defining an axial center of the tool body, wherein at least one of the first sidewall and the second sidewall is inclined toward the other in a direction extending from a base of the slot toward an opening of the slot; 
 at least one fixed blade associated with the tool body and configured to carry a fixed cutting element; 
 at least one leg configured to carry a rolling cutter, a portion of the leg disposed within the slot of the tool body and abutting the first sidewall; and 
 a wedge disposed within the slot and pinning the leg to the tool body within the slot. 
 
     
     
       2. The earth-boring rotary tool of  claim 1 , wherein the leg is not welded to the tool body. 
     
     
       3. The earth-boring rotary tool of  claim 2 , further comprising at least one fastener fastening the leg to the tool body. 
     
     
       4. The earth-boring rotary tool of  claim 2 , wherein the wedge is welded to the tool body. 
     
     
       5. The earth-boring rotary tool of  claim 2 , further comprising at least one fastener fastening the wedge to the tool body. 
     
     
       6. The earth-boring rotary tool of  claim 5 , wherein the at least one fastener fastening the wedge to the tool body extends through the wedge and partially through the tool body in a direction transverse to the longitudinal axis of the tool body. 
     
     
       7. The earth-boring rotary tool of  claim 5 , wherein the fastener is welded to the wedge. 
     
     
       8. The earth-boring rotary tool of  claim 2 , wherein the slot, the leg, and the wedge are configured such that a longitudinal position of the leg relative to the tool body is adjustable by sliding the leg in the slot in a direction parallel to the longitudinal axis defining an axial center of the tool body. 
     
     
       9. The earth-boring rotary tool of  claim 1 , wherein the third sidewall is flat or curved. 
     
     
       10. The earth-boring rotary tool of  claim 1 , wherein the first sidewall is inclined toward the second sidewall at an acute angle, and wherein the second sidewall is inclined away from the first sidewall at an obtuse angle. 
     
     
       11. The earth-boring rotary tool of  claim 10 , wherein the leg has a first surface on a first sidewall thereof and a second surface on a second sidewall thereof, the first surface inclined at an acute angle toward the second surface, the second surface inclined at an acute angle toward the first surface, the first surface of the leg abutting the first sidewall of the tool body, the second surface of the leg abutting the wedge. 
     
     
       12. The earth-boring rotary tool of  claim 11 , wherein the wedge has a first surface on a first sidewall thereof and a second surface on a second sidewall thereof, the first surface of the wedge inclined at an obtuse angle away from the second surface of the wedge, the second surface of the wedge inclined at an obtuse angle away from the first surface of the wedge, the first surface of the wedge abutting the second surface of the leg, the second surface of the wedge abutting the second sidewall of the tool body. 
     
     
       13. The earth-boring rotary tool of  claim 1 , wherein an axial end of the leg abuts against the axial end wall of the tool body. 
     
     
       14. The earth-boring rotary tool of  claim 1 , wherein the leg includes a key, and the tool body includes a keyway formed in at least one of the first sidewall, the second sidewall, or the third sidewall, the key extending into the keyway. 
     
     
       15. The earth-boring rotary tool of  claim 14 , wherein the key and the keyway are located and configured such that an end of the key will abut against the tool body and carry at least some of a compressive axial load applied between the leg and the tool body during use of the earth-boring rotary tool. 
     
     
       16. The earth-boring rotary tool of  claim 15 , wherein the key and the keyway are located and configured such that another end of the key will abut against the tool body and carry at least some of a tensile axial load applied between the leg and the tool body during use of the earth-boring rotary tool. 
     
     
       17. The earth-boring rotary tool of  claim 14 , wherein the key comprises an integral portion of the leg projecting radially relative to the longitudinal axis of the tool body, and wherein the keyway comprises a recess in the at least one of the first sidewall, the second sidewall, or the third sidewall, the recess having a geometry complementary to a geometry of the integral portion of the leg projecting radially relative to the longitudinal axis of the tool body. 
     
     
       18. The earth-boring rotary tool of  claim 1 , wherein the earth-boring rotary tool is a hybrid drill bit. 
     
     
       19. A method of forming an earth-boring rotary tool, comprising:
 forming a tool body having a slot at least partially defined by a first sidewall, an second sidewall opposing the first sidewall, a third sidewall extending between the first sidewall and the second sidewall, and an axial end wall of the tool body, the slot extending longitudinally parallel to a longitudinal axis defining an axial center of the tool body, wherein at least one of the first sidewall and the second sidewall is inclined toward the other in a direction extending from a base of the slot toward an opening of the slot, the tool body further comprising at least one fixed blade configured to carry a fixed cutting element; 
 forming at least one leg configured to carry a rolling cutter; 
 disposing a portion of the leg within the slot of the tool body and abutting a surface of the at least one leg against the first sidewall of the tool body; and 
 disposing a wedge within the slot, the wedge pinning the leg to the tool body within the slot. 
 
     
     
       20. An earth-boring rotary tool, comprising:
 a tool body having a slot at least partially defined by a first sidewall, a second sidewall opposing the first sidewall, a third sidewall extending between the first sidewall and the second sidewall, and an axial end wall of the tool body, the slot extending longitudinally parallel to a longitudinal axis defining an axial center of the tool body wherein the first sidewall is inclined toward the second sidewall at an acute angle, and wherein the second sidewall is inclined away from the first sidewall at an obtuse angle; 
 at least one fixed blade associated with the tool body and configured to carry a fixed cutting element; 
 at least one leg configured to carry a rolling cutter, a portion of the leg disposed within the slot of the tool body and abutting the first sidewall; and
 a wedge disposed within the slot and pinning the leg to the tool body within the slot.